I had an extra set from my old wj, thought I might give it a shot to see if it fits. Would have been a nice alternative for a winter set. Here are the results;
http://i46.photobucket.com/albums/f130/tonyl27/DSC00362.jpg
http://i46.photobucket.com/albums/f130/tonyl27/DSC00363.jpg
http://i46.photobucket.com/albums/f130/tonyl27/DSC00363.jpg
http://i46.photobucket.com/albums/f130/tonyl27/DSC00361.jpg
http://i46.photobucket.com/albums/f130/tonyl27/DSC00364.jpg

Just not enough clearence on the sides of the caliper. 19's would fit perfect. The off-set seems good almost flush with the fender and the face of the caliper cleared the wheels. These are Moda r6's, 18x9 with 255-55 on them custom powdercoated anthracite. Now they will be officially up for sale since I can't use them..

just a little teaser pic, I see quite a few on here have m3's.:)
http://i46.photobucket.com/albums/f130/tonyl27/DSC00366.jpg

I may be interested in the 18s. How much shipped to 29407?

Thank you VERY MUCH for that series of VERY helpfull photos... Looks like my calculations were correct..